Flap coverage of pressure sores

What the Anesthesiologist Should Know before the Operative Procedure

Patients requiring flap surgery for pressure sores are generally patients with chronic medical conditions. These patients are often either acutely or chronically immobile. Acute immobility may be from cardiovascular disease, acute neurologic disease, or orthopedic injury. Chronic immobility may be from spinal cord injury (SCI), cerebral palsy or other neuromuscular disorder. These comorbidities should be considered and evaluated prior to surgery to optimize the patient in all respects.

A preoperative discussion with the surgeon should include:

1. Location of pressure sore to be treated,

2. Location of the flap to be taken,

3. Positioning of the patient during surgery and any changes in position intraoperatively,

4. Plan for postoperative relief of pressure on the flap,

5. Plan for postoperative relief of involuntary muscle spasms if necessary.

Flap surgeries for pressure sores have a very high failure rate in the adult population, with an incidence between 25% and 85%. To improve the chances of successful flap surgery:

• Acute infections should be fully treated prior to surgery to prevent damage to a new flap.

• The patient’s nutritional status should be optimized to encourage tissue growth.

• Patients should be encouraged to stop smoking, drinking alcohol, or using illicit drugs in an effort to improve wound healing.

• Patients should also be hemodynamically stable preoperatively as vasopressors may decrease blood flow to a new flap.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

Flap surgery for pressure sores is purely elective. There is no urgency for this surgery, since pressure sores can be managed conservatively by optimizing patient nutrition, treating the underlying etiology of the pressure sore, and maintaining proper wound care. Many patients may benefit from this surgery but are not offered surgery given the high risk of flap failure.

Elective: This is a purely elective case. Patient should be medically and nutritionally optimized prior to going to the operating room (OR).

2. Preoperative evaluation

Cardiovascular disease

Patients with pressure ulcers often have co-morbid cardiovascular conditions. Surgery for pressure sores is purely elective, and patients should receive a full preoperative evaluation as indicated by the American Heart Association guidelines for non-cardiac surgery.

Diabetes mellitus

Poor glycemic control is common in patients with pressure sores, and poor glycemic control is a predictor of poor wound healing. Glycemic control should be optimized, and the patient’s medication regime stabilized before the patient presents for surgery.

Pulmonary disease

Smoking worsens wound healing and may be a risk factor for pressure sores. Smoking can predispose patients to diseases such as asthma and chronic obstructive pulmonary disease (COPD). As surgery for flaps for pressure sores is elective, the management of these conditions should be optimized pre-operatively.

Hemodynamic stability

Surgery to create flaps for pressure sores can result in significant blood loss. As such, it is prudent to have blood typed and crossmatched before the patient arrives in the OR. Additionally, intraoperative vasopressor support is generally discouraged as it may lead to flap ischemia.

Neuromuscular disease

Neuromuscular disease may result in immobility that leads to the formation of pressure sores. A preoperative neurologic exam will help identify pre-existing neurologic deficits and dictate limitations associated with positioning during surgery. As such, the anesthesiologist should have a preoperative discussion with the surgeon about how best to position and pad the patient during surgery.

Medically unstable conditions warranting further evaluation include cardiovascular, pulmonary, endocrine, and infectious disease.

Delaying surgery may be indicated if the patient presents with an unstable medical condition. Flaps for pressure sores are purely elective and the presence of unstable disease is a contraindication to surgery as it may effect the health of the patient and the negatively impact success of the flap.

3. What are the implications of co-existing disease on perioperative care?

N/A

b. Cardiovascular system

Acute/unstable cardiac conditions such as unstable coronary artery disease (e.g., angina or acute myocardial infarction [MI]), new onset of decompensated congested heart failure (CHF), new or significant arrhythmias (e.g., atrial fibrillation with rapid ventricular response, or heart block), symptomatic bradycardia, or severe valvular disease are all contraindications to elective surgery according to American Heart Association (AHA) guidelines. Each of these conditions must be optimized before a patient is considered for elective flap surgery. Preoperative tests including electrocardiogram (ECG), transthoracic echocardiogram (TTE), lab tests for cardiac biomarkers, stress testing, and cardiac catheterization may aid in the diagnosis of these conditions where appropriate.

Baseline coronary artery disease or cardiac dysfunction – Goals of management: many patients presenting for flap surgery will also have coronary artery disease. The anesthesiologist should follow the AHA guidelines for perioperative cardiovascular evaluation and testing. It is important to determine the patient’s baseline functional status and review any pre-existing cardiac testing (e.g., ECG, TEE, and stress testing). Additional testing should be ordered if it will influence anesthetic management. Heart rate control should also be considered where appropriate. In all ways, the patient’s cardiovascular disease should be optimized prior to presenting for flap surgery.

Hypertension: the patient’s blood pressure should be medically optimized before any elective surgery. Anti-hypertensives are continued in the perioperative period, with the notable exception of ACE Inhibitors. ACE Inhibitors are held on the day or surgery to minimize intra-operative hypotension.

Hypotension: should be investigated pre-operatively and have its root cause identified and treated. Flap surgery may involve a significant amount of blood loss, so patients presenting to the operating room (OR) should be hemodynamically stable before induction of anesthesia.

c. Pulmonary

COPD

Pulmonary function should be optimized before elective flap closure. Patients with severe pulmonary disease may need active co-management by pulmonary physicians. Smoking cessation should be encouraged preoperatively in order to improve overall health and facilitate wound healing. Pre-operative pulmonary function testing should be considered in patients with severe disease or where it will effect peri-operative management. On the day of surgery, a through history and physical exam focusing on recent upper and lower respiratory tract symptoms and exam findings may help delineate patients who are optimized for surgery versus patients who need further medical management.

Reactive airway disease (asthma)

As with patients with COPD, preoperative optimization is key to successful peri-operative management. Again, smoking cessation is important and should be encouraged pre-operatively. Pulmonary function testing can be pursued in cases of severe disease if it will effect peri-operative management. On the day of surgery, a thorough history and physical exam can determine if a patient should proceed with surgery or be delayed for further medical management.

d. Renal-GI:

Perioperative evaluation

Baseline creatinine may provide baseline information about renal function.

A history of gastroesophageal reflux (GERD) may require a rapid sequence induction to facilitate airway protection.

Perioperative risk reduction strategies

Intraoperative hypotension with associated low urine output is likely caused by insensible losses, surgical blood loss, and minimal stimulation from the surgery itself. To restore normal hemodynamics, administration of crystalloids and possibly colloids are preferable to use of vasopressors as vasopressors may lead to vascular constriction in the flap.

e. Neurologic:

Perioperative evaluation

Baseline neurologic examination should be performed and documented.

Perioperative risk reduction strategies

If there are active acute neurologic issues (e.g., ischemic or haemorrhagic stroke), review neurology recommendations regarding target blood pressure. Also, avoidance of succinylcholine may be indicated to avoid life-threatening hyperkalemia from upregulated acetylcholine receptors.

f. Endocrine:

Perioperative evaluation

Evaluate for diabetes and review regular medications taken to control blood sugars. Evaluate for preexisting complications from diabetes, such as neuropathy, which may inhibit wound healing.

Perioperative risk reduction strategies

If the patient is diabetic, blood sugar should be checked regularly throughout the surgery, and both hyperglycemia and hypoglycemia should be avoided.

g. Additional systems/conditions that may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (e.g., musculoskeletal in orthopedic procedures, hematologic in a cancer patient).

N/A

4. What are the patient’s medications and how should they be managed in the perioperative period?

In general, patients should continue to take their preoperative medications during the perioperative period. Patients who take chronic pain medications should continue their baseline pain regimens to assist with adequate pain control post-operatively.

h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

Oral hypoglycemics: these medications are often held the morning of surgery.

Insulin dosing: these medications are often adjusted for the fasting period preoperatively.

ACEIs: these medications are often held the morning of surgery to minimize intraoperative hypotension.

Baclofen: frequently used PO or intrathecal to relieve spasticity in patients with spinal cord injury (SCI) and multiple sclerosis. There are case reports of seizure-like activity in patients taking baclofen who are induced with propofol. Acute withdrawal from baclofen may cause seizures and hallucinations; thus, baclofen should be continued until surgery.

i. What should be recommended with regard to continuation of medications taken chronically?

Cardiac: Continue normal medication but consider holding ACE Inhibitors on the day of surgery.

Pulmonary, renal, neurologic, and psychiatric: Continue normal medications.

Antiplatelet: Discuss continuation of antiplatelet medication with surgical and medical teams.

j. How To modify care for patients with known allergies –

Avoid giving known allergens to patients.

k. Latex allergy- If the patient has a sensitivity to latex (e.g., rash from gloves, underwear, etc.), prepare the operating room with latex-free products.

Patients who are immobilized by chronic conditions are more likely to have had repeated exposure to latex and develop a latex allergy. If there is a known latex allergy, the operating room, including all anesthetic equipment should be latex-free. If medication vials contain latex, use equipment to remove the top of the vial before entering the vial.

l. Does the patient have any antibiotic allergies- – Common antibiotic allergies and alternative antibiotics]

Penicillin is a particularly common allergy. Depending on the severity of the reaction, it may be reasonable to administer a cephalosporin in the perioperative period. However, depending on the severity of the reaction, alternate antibiotics such as clindamycin or vancomycin may be necessary. In any event, all patients should be monitored for allergic reactions whenever antibiotics are administered.

m. Does the patient have a history of allergy to anesthesia?

Malignant hyperthermia

Documented: Avoid all trigger agents such as succinylcholine and inhalational agents.

• Proposed general anesthetic plan: prepare anesthesia machine using clean technique; provide TIVA (total intravenous anesthesia)

• Ensure malignant hyperthermia (MH) cart available [MH protocol]

Family history or risk factors for MH: if known family history of MH or risk factors for MH, it is prudent to provide an anesthetic with a clean technique and TIVA.

Local anesthetics/muscle relaxants

Allergies to ester local anesthetics are not uncommon. Ensure that surgeon is aware of local anesthetic allergy and verify that local anesthetics are not present on the surgical field. Anesthesia providers should provide analgesia without local anesthetics.

If a patient has a known allergy to a muscle relaxant, choose an alternate muscle relaxant. Alternatively, consider performing anesthetic without relaxation as the surgical procedure usually does not require relaxation.

5. What laboratory tests should be obtained and has everything been reviewed?

This is an elective procedure that should be performed when the patient’s medical conditions, including nutrition, are optimized. Preoperative labs that should be obtained are a hematocrit to evaluate for preoperative anemia as well as a full set of electrolytes.

Hemoglobin levels: Evaluate hemoglobin (Hgb)/hematocrit (Hct) for anemia because the patient may experience some blood loss. Therefore, a baseline Hct would be useful to calculate Maximum Allowable Blood Loss.

Electrolytes: Check electrolytes to evaluate renal function. Also check magnesium (Mg) and phosphorus (Phos) because these patients are frequently malnourished.

Coagulation panel: If there are reasons to suspect coagulopathy, check international normalized ratio (INR), prothrombin time (PT) and platelets.

Imaging: Imaging may be indicated by the patient’s history or physical. However, routine imaging is not necessary.

Other tests: Check white blood cells (WBCs) if there is concern that the patient’s pressure sore may be infected.

Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

Although regional anesthetics may be used for postoperative analgesia, the primary anesthetic is usually general endotracheal anesthesia (GETA). GETA is the preferred anesthetic choice because these cases are long and the patients may require unique positioning.

Regional anesthesia

Depending on the location of the flap and ulcer, regional anesthesia may be possible for intraoperative anesthesia or postoperative analgesia.

Neuraxial

Benefits: Neuraxial anesthesia avoids manipulation of the airway and may lead to improved post-operative pain. Neuraxial anesthesia may be performed in addition to a general anesthetic.

Drawbacks: Patients are often placed in the prone position for this procedure, and modifying the anesthetic from monitored anesthesia care to general anesthesia can create unique challenges.

Issues: Ensure no infection in site of block placement.

Peripheral nerve block

Benefits: Peripheral nerve blocks may provide some postoperative analgesia.

Drawbacks: Peripheral nerve blocks usually require multiple blocks for complete pain control because two sites will be involved in surgery (e.g., donor and target site).

Issues: May consider regional anesthesia postoperatively to extend length of analgesia and to be sure block placed in correct area (i.e., surgeons did not change plan for flap intraoperatively).

General anesthesia

Benefits: General anesthesia allows the anaesthesia provider to protect the patient’s airway, control ventilation, and provide muscle relaxation.

Drawbacks: Hypotension may be associated with volatile anesthetics, and anesthetics have multiple end-organ effects. Also, patients who receive general anesthesia will require additional postoperative analgesia.

Airway concerns: If there has been long-standing immobility, succinylcholine is likely contraindicated as it may lead to profound hyperkalemia.

Monitored anesthesia care

Benefits: Minimal; if light MAC is used, there are minimal risks from malpositioning.

Drawbacks: This patient population tends to have multiple chronic medical problems including cardiac, pulmonary and neurologic disease. The patient is likely to be placed in the prone position, and the procedure may last several hours. This combination may lead to very long MAC in a prone patient with an unprotected airway.

6. What is the author’s preferred method of anesthesia technique and why?

GETA is the preferred technique because flap surgeries may take many hours, and the procedure is often performed in the prone position. A secure airway and more optimal control over ventilation and hemodynamics contribute to a more stable anesthetic.

What prophylactic antibiotics should be administered?

If prophylactic antibiotics are to be given, they should be given within 1 hour of incision and redosed in accordance with your institution’s recommendations. At this point, there is no evidence that use of prophylactic antibiotics in clean plastic surgery is effective, so antibiotic administration will often be dictated by local preferences. A commonly used regimen is a first or second-generation cephalosporin, such as cefazolin 2 g, redosed every 4 hours during surgery, and discontinued within 24 hours.

What do I need to know about the surgical technique to optimize my anesthetic care?

Positioning: Patient positioning should be discussed with the surgeon preoperatively. There may be position changes intraoperatively for optimal surgical access. The movement of the patient should be well choreographed to avoid injuring the patient or damaging the flap.

Relaxation: if there is a flap with a vascular anastomosis planned, patient movement can have devastating effects on the surgery and should be avoided. Thus, relaxation may be utilized.

What can I do intraoperatively to assist the surgeon and optimize patient care?

Bleeding: Flap surgery may have significant amount of exposed tissue that can bleed. Intraoperative blood loss may be decreased by maintaining blood pressure on the lower range of normal while taking care to maintain perfusion to vital organs.

Oxygenation: Postoperative flap perfusion may be monitored via Doppler or with oxygen saturation.

Hypothermia: Ensure that the patient is normothermic since hypothermia can lead to coagulopathy and aggravate surgical bleeding.

What are the most common intraoperative complications, and how can they be avoided/treated?

Hypotension/low urine output: Determine the underlying cause of hypothermia and oliguria while keeping in mind that the hypotension and low urine output may be related to insensible fluid losses and bleeding. Hypotension and oliguria will likely respond to crystalloids and colloids.

Bleeding: Intraoperative bleeding may be difficult to quantify due to significant lavage of the ulcerated site. Transfusion may be necessary, and it is important to have the patient’s blood typed and screened.

a. Neurologic:

Prone positioning requires vigilance on the part of the surgeon and the anesthesiologist. Patients in the prone position are at increased risk for peri-operative vision loss or damage. Careful attention should be paid to ensuring that the patient’s eyes are gently taped shut and are free of pressure in a prone pillow. Additionally, the anesthesia provider should make sure that the patient’s neck is in a neutral position and that venous return from the head is unimpeded by positioning.

Patients presenting for flap surgery often have advanced cardiovascular disease and may also have suffered from a prior cerebrovascular accident (CVA). As such, blood pressure may need to be aggressively managed to ensure adequate cerebral blood flow. Venous return from the head and neck should also be unobstructed by positioning.

b. If the patient is intubated, are there any special criteria for extubation?

Extubation should be performed in a manner that will prevent coughing and or other increases in intrathoracic pressure. As the new flap will often be located on the dependent side of the patient’s body, the patient will need to be placed in the prone position for surgery before being placed supine for extubation. Then, following extubation, the patient may need to be returned to the prone position to avoid applying pressure to the new flap. Any unplanned movement could cause the flap to tear and ultimately fail. Thus, extubation should be done in a very controlled manner with the patient having received adequate analgesia.

c. Postoperative management

What analgesic modalities can I implement?

The amount of analgesia required will depend on how much of the surgery was done in a sensate area and what tissues are involved (skin, subcutaneous tissue and/or muscle). Opiates should be titrated to effect. If the surgery was performed in an area that would be amenable to placing an epidural, this may be a preferred method of analgesia because in patients with muscle spasticity, this may help decrease muscle spasticity and decrease tension on the flap. If the flap is in an area amenable to a regional anesthetic, this may be considered for post operative pain control as well.

What level bed acuity is appropriate?

Even if extubated and hemodynamically stable, the patient will likely require intensive care unit (ICU) care for the first 24 hours to allow for frequent flap checks.

What are common postoperative complications, and ways to prevent and treat them?

Postoperative bleeding/hematoma: Postoperative position is very important; no pressure should be placed on the new flap to minimize postoperative bleeding and/or hematoma formation.

Hypothermia: Fluid warmers and forced hot-air warmers should be used intraoperatively and possibly postoperatively to avoid vasoconstriction in the flap area.

Hypovolemia: Depending on the extent of the surgery, significant blood loss, as well as significant evaporative losses, may occur because of the large tissue area exposed for a prolonged time. Adequate intraoperative and postoperative fluid resuscitation is key to treat hypovolemia.

What’s the Evidence?

Bauer, J, Phillips, LG. “MOC-PS CME Article: Pressure sores”. Plast Reconstr Surg. vol. 121. 2008. pp. 1-10. (Describes the physiology of pressure sore development, describes risk factors and which population of patients develop pressure sores, describes common surgical treatment and prevention strategies.)

McCarthy, V, Lobay, G, Matthey, PW. “Epidural anesthesia as a technique to control spasticity after surgery in a patient with spinal cord injury”. Plast Reconstr Surg. vol. 112. 2003. pp. 1729-30. (Describes the utility of epidural anesthesia in controlling spasticity in patients with spinal cord injuries.)

Fleisher, LA, Beckman, JA, Brown, KA, Calkins, H, Chaikof, EL, Fleischmann, KE, Freeman, WK, Froehlich, JB, Kasper, EK, Kersten, JR, Riegel, B, Robb, JF. “2009 ACCF/AHA focused update on perioperative beta blockade incorporated into the ACC/AHA 2007 guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines”. Circulation. vol. 120. 2009. pp. e169-276. (The guidelines for perioperative testing in patients undergoing noncardiac surgery.)

Edgcombe, H, Carter, K, Yarrow, S. “Anaesthesia in the prone position”. Br J Anaesth. vol. 100. 2008. pp. 165-83. (Describes the physiological changes which occur on prone positioning. Also describes the risks of prone positioning and how to minimize risks.)

Bratzler, DW, Houck, PM. “Antimicrobial prophylaxis for surgery: an advisory statement from the National Surgical Infection Prevention Program”. Am J Surg. vol. 189. 2005. pp. 395-404. (Goes through SCIP guidelines. consider also reading Bratzler DW The surgical infection prevention and surgical care improvement projects: promises and pitfalls. Am Surg 2006;72:1010-6. This also reviews the rationale for SCIP and the measures that are being collected and the outcomes that are being monitored.)

Tadiparthi, S. “Prophylactic antibiotics for clean, non-implant plastic surgery: what is the evidence”. J Wound Care. vol. 17. 2008. pp. 392-4.

Munroe, MM, McClelland, J, Swide, C. “Vasopressor use in free tissue transfer surgery”. Otolaryngol Head Neck Surg. vol. 142. 2010. pp. 169-73.

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